Surfactant compositions containing a polyoxyethylene-based nonionic surfactant and an anionic surfactant together have high detergency and are widely used as a detergent, mixed with a diluent such as water.
Such a detergent containing a polyoxyethylene-based nonionic surfactant, an anionic surfactant, and water is however known to also exhibit a drastic decrease in fluidity under a cool temperature environment, which is difficult to handle, and further cause unfavorable phenomena accompanied by a decreased stability, such as separation and clouding. Methods for solving these problems generally contain addition of a solvent or the like and use of a surfactant at a certain concentration set to low. However, in some cases, addition of a solvent in an increased amount unfavorably leads to an inflammable detergent and adversely affects performances of a surfactant itself more than a little. Use of a surfactant at a low concentration has a problem of decreased fundamental performances such as detergency of a detergent composition.
To solve these problems, JP-A 53-58508 discloses a liquid detergent containing a polyoxypropylenepolyoxyethylene alkyl ether and a polyoxyethylene alkyl ether sulfate together, that exhibits good fluidity and stability at low temperature. WO-A 98/24865 discloses a surfactant composition containing an anionic surfactant and a nonionic surfactant prepared by adding ethylene oxide, propylene oxide, and ethylene oxide to a higher alcohol in this order, that is easy to handle and has good detergency. WO-A 2009/008542 discloses a surfactant containing an alkyl ether sulfuric acid ester salt.